D7122: copies: avoid instancing more changectx to access parent revisions

[marmoute (Pierre-Yves David)]

marmoute created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  We just need to know the revision numbers of the parents, creating full context
  is needlessly expensive.
  
  This provide a small, but noticeable performance boost.
  
  revision: large amount; added files: large amount; rename small amount; c3b14617fbd7 9ba6ab77fd29
  before: ! wall 2.885636 comb 2.900000 user 2.870000 sys 0.030000 (median of 10)
  after:  ! wall 2.702270 comb 2.710000 user 2.690000 sys 0.020000 (median of 10)
  revision: large amount; added files: small amount; rename small amount; c3b14617fbd7 f650a9b140d2
  before: ! wall 4.298271 comb 4.290000 user 4.240000 sys 0.050000 (median of 10)
  after:  ! wall 3.976610 comb 3.970000 user 3.920000 sys 0.050000 (median of 10)
  revision: large amount; added files: large amount; rename large amount; 08ea3258278e d9fa043f30c0
  before: ! wall 0.773397 comb 0.770000 user 0.770000 sys 0.000000 (median of 11)
  after:  ! wall 0.701634 comb 0.700000 user 0.700000 sys 0.000000 (median of 13)
  revision: small amount; added files: large amount; rename large amount; df6f7a526b60 a83dc6a2d56f
  before: ! wall 0.013585 comb 0.010000 user 0.010000 sys 0.000000 (median of 217)
  after:  ! wall 0.013550 comb 0.010000 user 0.010000 sys 0.000000 (median of 218)
  revision: small amount; added files: large amount; rename small amount; 4aa4e1f8e19a 169138063d63
  before: ! wall 0.003202 comb 0.000000 user 0.000000 sys 0.000000 (median of 929)
  after:  ! wall 0.002993 comb 0.010000 user 0.010000 sys 0.000000 (median of 992)
  revision: small amount; added files: small amount; rename small amount; 4bc173b045a6 964879152e2e
  before: ! wall 0.000077 comb 0.000000 user 0.000000 sys 0.000000 (median of 12060)
  after:  ! wall 0.000072 comb 0.000000 user 0.000000 sys 0.000000 (median of 12804)
  revision: medium amount; added files: large amount; rename medium amount; c95f1ced15f2 2c68e87c3efe
  before: ! wall 0.510614 comb 0.500000 user 0.500000 sys 0.000000 (median of 18)
  after:  ! wall 0.473681 comb 0.470000 user 0.470000 sys 0.000000 (median of 20)
  revision: medium amount; added files: medium amount; rename small amount; d343da0c55a8 d7746d32bf9d
  before: ! wall 0.126552 comb 0.130000 user 0.130000 sys 0.000000 (median of 77)
  after:  ! wall 0.115240 comb 0.110000 user 0.110000 sys 0.000000 (median of 85)

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D7122

AFFECTED FILES
  mercurial/copies.py

CHANGE DETAILS

diff --git a/mercurial/copies.py b/mercurial/copies.py
--- a/mercurial/copies.py
+++ b/mercurial/copies.py
@@ -207,12 +207,13 @@
             return copies
         for i, c in enumerate(children[r]):
             childctx = repo[c]
+            p1, p2 = cl.parentrevs(c)
             p1copies, p2copies = childctx._copies
-            if r == childctx.p1().rev():
+            if r == p1:
                 parent = 1
                 childcopies = p1copies
             else:
-                assert r == childctx.p2().rev()
+                assert r == p2
                 parent = 2
                 childcopies = p2copies
             if not alwaysmatch:



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